The present invention is directed to a method and a system for solvent purification. Synthetic and organo-metallic chemistry for example requires very high purity solvents. More specifically, synthetic chemistry requires solvents which are deplete of oxygen and moisture content. Organo-metallic chemistry requires solvents which even have a higher purity as to moisture content. In other words, the solvent needs to be “dry” before it can be used
A traditional method for purifying or “drying out” solvents is thermal distillation. Because solvents are very volatile, thermal distillation presents a significant fire and explosion hazard. In addition, it is a very inefficient method for drying out the solvent. Typically, distillation involves use of a suitable drying agent. A typical drying agent may be Li, Na, K, CaH2, and LiA1H4. These drying agents are highly reactive and as such are quite dangerous. Over the years there have been many fires and explosions involving thermal distillations of solvents. Chemists characterize thermal distillation as one of the most dangerous routine procedures they perform. Moreover, the maintenance of distillation equipment and the quenching of the drying agents are very laborious.
Another purification method uses the so-called “Grubbs apparatus” which uses a very large solvent reservoir and alumina/catalyst columns to dry and de-oxygenate solvents to the desired level of purity, without using heat or water reactive drying agents. The Grubbs apparatus takes up a lot of laboratory and research space. The system uses a large storage drum holding 15-20 liters of solvent and purification columns or cylinders that are typically over 30 inches tall and have a diameter greater than 3 inches. Multiple columns are used and are connected in series. Each of the column contains an activated filter media that removes contaminates from a solvent as it passes through the column. The solvent is passed only once through the columns to get filtered. By the time the solvent reaches the end of the last column, the solvent is sufficiently filtered.
Filling of the drum reservoir with a solvent typically occurs under a fume hood for the purpose of evacuating all hazardous solvent fumes. Solvents may be provided in 4 liter containers. Thus, multiple containers must be used to fill the drum. Solvents may also be provided in larger containers, as for example, 10 or 20 liter containers. Such containers are typically heavy. Moreover, it may be difficult or impossible to empty such containers into the drum reservoir while under a fume hood.
Furthermore, after use, each of the long columns must be regenerated, i.e., the contaminates which had been filtered out from the solvent must be removed from the columns. This may be quite difficult as the cylinders are long. The problem with the Grubb system is that it is not portable and due to its size it is confined to the space upon where the system is housed.